avian filarioid nematodes of the world - integrative …...avian filarioid nematodes of the world...

Cheryl M. Bartlett, PhDCanada Research Chair in Integrative ScienceProfessor of Biology Sydney, Nova Scotia

Annual International Conference

Avian Filarioid Nematodes of the World

3-8 August 2008

ABSTRACT: Filarioids are highly specialized nematode parasites whose adults live in the tissues and tissue spaces of birds, mammals, amphibians, and reptiles. Females produce microfilariae (MF) that enter the host’s blood or skin. Synoptic understandings about filarioids in birds, especially their diversity, distributions, and pathogenicity are now available for the first time with the completion of an extensive literature review. Such reveals about 160 described species and 16 valid genera. Only Pelecitus occurs in hosts other than just birds and, while considerable host survey work remains to be done, Pelecitusalso appears to be the most broadly distributed genus with reports from 17 avian orders. Chandlerella is known from 13 and Paronchocerca,Splendidofilaria and Cardiofilaria from 11. With notable exceptions, avian filarioids are not pathogenic, and most cases are associated with adult worms in the heart muscles or lumen, major blood vessels, or brain (e.g. some species of Sarconema, Paronchocerca, Chandlerella, and Splendidofilaria) or near joints in the legs and feet (e.g. species of Pelecitus). However, the majority of species whose adults live in these sites are not pathogenic. Moreover, a species pathogenic in an individual bird may not be pathogenic in other birds of the same species. And, worms pathogenic in one or more species of birds may not be pathogenic in other species. Pathogenicity is even more rarely reported in association with MF. The normally blood-borne MF of Splendidofilaria caperata become trapped and provoke chronic inflammation in tissues near adults in crows. Skin-inhabiting MF of Eulimdana clava might be a factor in feather loss in pigeons.

based on Chapter 26

by C. Bartlett

2008

Avian Filarioid Nematodes

6 major topicsSYNOPSIS

Life Cycle

Vectors

Host Distributions

Pathogens


based on Bartlett 2008,Chapter 26 in:

SYNOPSIS

Biodiversity

Sites in Bird Host

} editedby


BiodiversityNematodaOrder SpiruridaSuperfamily Filarioidea

1

parasites of:birds,

mammals, reptiles,

amphibians

slender roundworm parasites


Biodiversity

≈ 160 valid species (numerous synonyms)

16 recognized genera (31 synonyms)

worldwide

NematodaOrder SpiruridaSuperfamily Filarioidea

widespread common

1

easily overlooked


NEVER: lumen of digestive or respiratory tracts or air sacs

Sites in Bird Host- adult worms

• diverse tissues & tissue spaces

• often very difficult to find

2a

easily overlooked


microfilariae (MF)

Sites in Bird Host- adult worms

2a

- microfilariae


• blood- “the rule” - species in

all genera

• skin - “little known”- some

species in2 genera

microfilariae (MF)

Sites in Bird Host2b


microfilariae

Sites in Bird Host- microfilariae

diverse MF morphology from Bartlett 2008 in Parasitic Diseases of Wild Birds

2b

microfilariae (MF)enter blood or skin

microfilariaeingested byvector


Life Cycle

3

microfilariae (MF)enter blood or skin

transmissionto bird

microfilariaeingested byvector

Avian Filarioid Nematodesdevelopment to infective stage

L3

3

Avian Filarioid NematodesVectors

Lice

Black Flies

Biting Midges

Mosquitoes

19 Filarioids5 spp. in 3 genera

2 spp. in 1 genus

3 spp. in 3 genera

9 spp. in 3 genera

EulimdanaSarconemaPelecitus

Splendidofilaria

CardiofilariaPelecitusAproctella

ChandlerellaEufilariaSplendidofilaria

**

4

MF in skin

Host Distributions

by bird order

Avian Filarioid Nematodes5a

Host Distributions27

bird

ord

ers

by bird order

16 parasite genera(adult parasites)

27 b

ird o

rder

s


27 b

ird o

rder

s

= reported


27 b

ird o

rder

sMF

= reported

3 orders ... no

reportsof

adultsorMF


27 b

ird o

rder

sMF

= reported

Rheiformes

Apterygiformes

Procellariiformes

3 orders ... no

reportsof

adultsorMF

5 parasite generabroad host distribution

27 b

ird o

rder

s

= reported

27 b

ird o

rder

s

Pelecitus

Chandlerella

Splendidofilaria

5 parasite generabroad host distribution17

13

11

Cardiofilaria11

Paronchocerca11

27 b

ird o

rder

s

Pelecitus

5 parasite generabroad host distribution

UNIQUE: species in birds

AND other vertebrates(mammals)

27 b

ird o

rder

s5 parasite genera

broad host distribution

Paronchocerca UNIQUE: each species (17)

specific to a bird family

Host Distributions: by bird family*

adult worms------------------

72 of 159 bird families

adult worms+ MF

-----------------96 of 159

bird families

* families as perHoward & Moore 1984

= reported

5b

• multiple infections (≥ 2 genera)- 4 genera especially relevant:Cardiofilaria, Chandlerella, Splendidofilaria, Eufilaria

• concurrent infections (≥ 2 spp. of same genus)- 2 genera especially relevant:Chandlerella, Splendidofilaria

re: same bird species OR individual bird

Host Distributions: by bird species 5c

Pathogens


6

GENERAL: very rarely pathogenic

Pathogens6

location & host identity important

GENERAL: very rarely pathogenic

• heart• blood vessels

• brain

• joints

• skin

adult wormsmicrofilariaePathogens

6

location & host identity important

Pathogens6

5 examples

BUT with each: NO clinical signs

or pathology innumerous bird

species

AND, for some,pathology NOT inevitable

in all individuals of same bird species

Sarconema eurycerca- in myocardium (also endocardium)

• heart

6.1

from: Kluge 1967, Bull. WDA: 3

Sarconema eurycerca- in myocardium (also endocardium)

Pathogen adult worms6.1

• heart

Sarconema eurycerca- in myocardium

Pathogen adult worms

from: Chapter 26 in Parasitic Diseases of Wild Birds

• myofiber separation; interstitial hemorrhage; mixed inflammatory infiltrate

• more advanced cases:necrosis and fibrosis

6.1

• heart

Splendidofilaria caperata- wall of pulmonary artery

6.2

• pulmonary artery

Pathogen adult wormsmicrofilariae

pub: Bartlett & Anderson 1981, JWD: 17

original

Splendidofilaria caperata- wall of pulmonary artery

6.2

• pulmonary artery

in American crows:• chronic inflammation• fibrosis

Chandlerella quiscali- between cerebral hemispheres

• brain

6.3

Chandlerella quiscali- between cerebral hemispheres

• brain

Pathogen

in farmed emus• clinical signs

adult worms6.3

• joints

Pelecitus spp.- among tendons

6.4

• joints

Pelecitus spp.- among tendons

Pathogens adult worms

NO clinical signs or pathology innumerous host

species

in red-necked grebes, rarely coots• chronic inflammation• fibrosis original

pub: Bartlett & Anderson 1989, CJZ: 67

in psittacids (esp. pets)• tenosynovitis• swollen feet

6.4

Eulimdana clava

Pathogen

• neck

6.5

clinical sign(isolated report)• extensivefeather loss

in neck region

Eulimdana clava

Pathogen

from: Guildal & Settnes 1968; Nord. Vet-Med: 20

adult worms

• neck

6.5


in neck region

Eulimdana clava

feat

her

louse vector

- microfilariae in skin*

Pathogen


in neck region

*

original(actually = MF of Pelecitus fulicaeatrae)

from: Guildal & Settnes 1968; Nord. Vet-Med: 20

adult worms

• neck

microfilariaeadult worms

agent?

6.5

Life Cycle

Vectors

Host Distributions

Pathogens


based on Bartlett 2008,Chapter 26 in:

SYNOPSIS

Biodiversity

Sites in Bird Host

} editedby

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